Is it possible to delete backfaces as opposed to hiding them?
It is impossible to delete backfaces, since they are only a concept in rendering algorithms - there is nothing to delete

Backface culling is a shading feature of the render engine that you are using. Back faces are not in any way stored with 3d data so there is nothing to delete. Backface is the back of a regular face that is determined by which direction the surface is facing or in other words - surface normals, that are definitely already included in your models when you export them from Blender or pretty much any other 3d app. No other information about back faces than surface normals is saved with the models so there is nothing more that can be done inside Blender. This features should be turned on or off in the game engine you are using. Backfaces might not be displayed by default in some rendering scenarios so it may also not be considered a feature at all, but actually the lack of another feature - backface shading, or double sided shading. It depends on how you look at it and how the shading works in a specific render engine.